The invention relates to a valve control unit, particularly for internal combustion engines, in which a valve is fixed on a valve spindle which is rotatably mounted in a valve body for angular movement by a control motor for positioning the valve, the motor being coupled to the valve spindle through a gear mechanism, a sensor unit being provided for sensing an adjusted position of the valve spindle, a cover being mountable on the valve body and supporting an electric clutch element.
Such valve control units are used, for example, to control flow of exhaust gases in a return line to the engine or as throttle-valve control units in the intake line of the internal combustion engine.
Such a valve control unit is disclosed in German Patent Application DE-OS 195 25 510 A1. In this valve control unit, the control motor as well as a mechanism connecting the control motor with the valve spindle is disposed in the throttle body. Furthermore, the positioning gear disposed on the valve spindle is provided with wiper elements which cooperate with a potentiometer. The potentiometer as well as electric leads, an electric clutch element and a plug-in motor contact connecting the electric clutch to the motor are disposed in the cover. The arrangement of the electric motor clutch is constructionally complex and is also sensitive to dirt and vibration, which can lead to interruption of the electrical contact.
An object of the invention is to provide a valve control unit which avoids the disadvantages of the conventional arrangement as described above.
This object is achieved by providing a bearing for an end of the motor shaft of the control motor, together with functional parts of the control motor, on the cover such that assembly of the control motor is completed upon mounting the cover on the valve body.
The valve control unit of the invention thereby can be made in particularly simple manner and at low cost. By mounting the bearing for the end of the motor shaft as well as important functional parts of the control motor on the cover, the complete electric motor clutch is obviated. The motor is assembled simply by mounting the cover in place on the valve body. A further advantage of this arrangement is that the output of motor power through the gear mechanism now takes place between two bearing points, whereby the force distribution on the motor shaft takes place in much more favorable manner.